Perpetual calendar



ullm-ATH' Oct. 19, 1954 LANGMAN 2,691,838

PERPETUAL CALENDAR Filed Dec. 2, 1949 INVE NTO R Hanny La mgm/aw ,z ATTOR NEY Patented Oct. 19, 1954 UNITED STATES PATENT OFFICE PERPETUAL CALENDAR Harry Langman, Boston, Mass. Application December 2, 1949, Serial No. 130,647 13 claims. (o1. io-113) It is among the objects of the invention to provide a perpetual calendar of simple construction, which by one single, simple adjustment is correctly set to provide the calendar for the entire twelve months of any selected year of one or of any century.

Another object is to provide a perpetual calendar of the above .type which necessitates no more than two imprinted elements readily correlated with each other for coordinated setting of the days of the week with the days of each month for any selected year of any century and which dispenses with the need of computation, consultation of tables, resort to window openings or concealment and by which in fact the entire irnprinted matter is at all times completely exposed to view in required correlation.

Another object is to provide a calendar of the above type which may be fabricated from ordinaryl paper stock at low cost and which may be utilized either for desk use or hungon the wall.

As conducive to a clear understanding of the invention, it is noted that while perpetual calendars appeal to those who are puzzle and problem minded, there is considerable practical demand for such calendars by accountants, business men vand lawyers for ready determination of the number of weeks in seme selected month, years past or years hence, or the day of the week on which any particular date occurred, information that is not-readily otherwise instantly available as to the future nor even as to the past, since the calendar for each year is commonly discarded after it has served its purpose.

It is a feature of the present invention to imprint the sequence of months and of days of each month on one chart, and to imprint the sequence of days of the week on another chart, and to provide in addition an index of years imprinted on the same unit with one or the other of said two charts and showing the sequence of years of the century, correlated lone with each column of days or with the days of the Week, depending on the chart upon which said index is imprinted. The year index numerals are so arranged that if once the calendar is correctly set, say for the current year, the shift to any other year is immediately indica-ted bythe index to eiTect an advance of one day tothe next ordinary year vand of two days when the next year is a leap year.

In addition the calendar may afford the correct reading for centuries other than the current century. To this end the calendar also affords an indexv for four consecutive centuries, which is all that is required, since the correct calendar for any .shown on the index of years are imprinted in a discriminating manner preferably in a distinct color, for instance red, as is also the 29th day of February, which day is disregarded in reading the calendar for any year other than a leapv year. Preferably however it is not merely the 29th of February that is imprinted in the discriminating color, but the calendar duplicates the months of January and February, the duplicate January and February calendar being in the discriminating color and including the extra day of the leap yea-r, the said extra calendar of January and February being used only for a leap year, and the regular January and February calendar being used for an ordinary year.

In a preferred embodiment the monthly calendar is imprinted in sets of two consecutive months so that the extra leapyear calendar of January and February is at one extremity of the calendar, readily to be used or disregarded as the .case may be. The calendar for each month has the usual seven columns and live rows, while the days of the week on the distinct chart are repeated in sequence for appropriate heading of the monthly calendar.

While the two charts that make up the perpetual calendar may be relatively movable in rectilinear direction for setting to the desired year, it is generally preferred to arrange them for relative rotation and this may be accomplished by imprinting them. on cylindrical, conical or spherical segments coordinated for relative rotation about a common axis, but ordinarily it is preferred for simplicity, compactness and low cost, to imprint the parts on coaxial discs having a common, central pivot axis to permit the relative adjustment for setting to any year.

In the accompanying drawings,

Fig. 1 shows a plan view of one simple form of the invention, and

Fig. I2 is a, View in longitudinal axial cross section, taken on line 2 2 of Fig. l.

The specific embodiment shown in the drawing and now to be described, isV only one of a number 3 of possible embodiments of the invention as dened by and within the scope of the accompanying claims.

Referring now to the drawings, the calendar in the particular embodiment shown indicates a disc shaped chart A centrally connected upon a larger chart B, preferably also a disc. The connection is preferably a pivot illustratively shown as an eyelet i to permit the upper outer disc A to be rotarily adjusted with respect to the larger chart B.

Upon the disc A is imprinted the complete calendar, showing the titles of the months and the days of the month but not identifying the days of the week. In addition the calendar for the months of January and February is duplicated in contrasting type or color, illustratively in red, to include the added day, February 29th or the leap year, said added calendar months of January and February being used only for leap years. Such contrasting color of imprint is suggested by the cross-hatching of such numerals. In order to maintain the additional leap year calendar readily available for use, without disturbing the continuity of the ordinary calendar, consecutive months are preferably arranged in pairs as shown, the odd numbered months being on the outer part of the disc A and the even numbered months being respectively in registry with and encompassed by the calendar for the associated odd month. Preferably as shown, the disc A is thus sub-divided into seven identical sectors l l, one for each pair of the twelve months of the year and an additional sector l2 for January and February of the leap year. Each sector is sub-divided into seven sub-sectors I3 corresponding to the days of each week of the ordinary calendar and each monthly calendar has ve rows i4, the months being imprinted with March 1st illustratively on the last sub-sector of the March sector, so that even February is shown with some days in each of the rive rows, February 1st of the ordinary year illustratively coming on the last sub-sector of its sector, and of the leap year on the sixth sub-sector of its sector, the nal day of February in each case appearing in the sixth sub-section. For the last ten months of a leap year there will thus be the required advance of two days with respect to the corresponding dates of the previous year.

The outer chart B is imprinted in the form of a crown encompassing the disc A, the sequence of the days of the week from Sunday through Saturday being repeated seven times as at I5, completely about the chart A of months and each day thus imprinted being of angular width equal to that cfa sub-sector, that is one forty-ninth of the periphery. It is clear that for each of the various settings in which a day on the outer chart B is in registry with a column of days on the chart A of months, there will be a correct and complete calendar for some year.

In order correctly to set the calendar for any given year, the index of years H5, that is for each of the 100 years of a century, is imprinted upon one of the charts, in the embodiment shown, upon the inner portion of the A chart of months. In this index the sequence of years from 00 to 99 is shown arranged consecutively each for coordination, preferably by alignment wtih a subsector of a column of days on the chart of months. The numeral for each year on this index is shown to the left of and in the sub-sector column adjoining that of the next lower numeral, except for the leap year numerals illustratively printed 4 in red, which are imprinted in the second subsector to the left of that of the next lower year number, that is to skip one sub-sector.

Since there are but forty-nine sub-sectors in the periphery to accommodate the numerals of the index of years, and one hundred such numerals are to be accommodated, and in addition the twenty-five skipped spaces for the leap years, the year numerals are imprinted in three concentric circles as Shown, the pass over from the outer circle of the index of years, to the median circle being shown at 323-39, and from the median circle to the inner circle being shown at I6-Tl.

If the calendar, as thus far described, is set to be correct for the current year, 1950, and an appropriate mark shows such setting, then the calendar may be readily set for any other year by simply turning the inner disc to place the numeral of such other year in the sector previously occupied by 50. That this is so is obvious since the ordinary year of 365 days has one day more than an even number of weeks and so the days of the week are advanced by one day in passing from any year to the next ordinary year and the advance is by two days for dates after February 29 in similarly passing to a leap year.

In order not to limit the calendar to the current or any other century, but to afford it universal applicability at least from the time that the current Gregorian calendar was adopted, to the indenite future, it is merely necessary to afford an index for each of four consecutive centuries, since the calendar for any one year is correct for four hundred years hence and for each multiple of four hundred years hence. In passing to the next century, the century year of which is not a leap year, there is a loss of two days and where the century year of the next century is itself a leap year, there is a loss of but one day. Accordingly to render the calendar useful for various centuries, it is merely necessary to imprint an index of centuries indicated at D, illustratively on the outer chart B at one region of the crown of week days and showing the year 1900 two days before the year 1800, the year 2000 which is a leap year one day before 1900, and the year 2100 two days prior to the year 2000. This result is rather neatly accomplished by imprinting the century index in the sequence 1900, 1800, 2100 and 2000 in sub-sector alignment with alternate days of the week, viz., respectively aligned with Sunday, Tuesday, Thursday and Saturday, as shown.

That the calendar repeats in a cycle of four hundred years upon which the latter feature of the calendar is predicated is easily demonstrated. An ordinary century has 36,524 days made up on one hundred ordinary years plus twenty-four rather than twenty-five leap years, bearing in mind that the ordinary century year, though a multiple of four, is not a leap year. Bearing in mind that the century year of each fourth century is a leap year, the number of days in four centuries is four times 36,524 plus l or 146,097, which is a multiple of seven. Y

The ordinary century of 36,524 days being two days short of a multiple of seven, this accounts for the loss of two days in passing from one century to the next, and the loss of only one day where said next or succeeding century year is itself a leap year.

Preferably the iinal two zeros of the year 2000 on the D index of centuries are imprinted in discriminating color, illustratively in red, to indicate that this isa leap year and the 00 limpr-int on. the C index of years has its rst Izero in regular color, illustratively black, .and the second zero in discriminating color, illusltratively'red, to indicate that the year in question is-an ordinary yearA or a leap year depending on whether it is aligned with 1800, 1900er 2100 von the one hand, or with 2000 on the other.

In v the illustrative embodiment shown, it is preferable to provide holes P illustratively seven `in-rnimber on the outer chart B to facilitate choice in hanging the calendar against the wall if desired,V and at the same time to maintain the current month uppermost.

While the lconstruction shown is in general preferred, it is obvious that for any setting it is merelynecessary toalign the selected year with the selected century and that the year and century indices need not necessarily be aligned with vor in registry lwith the columns of days on the month chart or the days on the day crown. Moreover the index ofyears could be scrambled if desired, because any year if imprinted at any multiple of seven spaces in advance or behind that shown or if printed in any of the three rings shown would give the correct calendar when set in the manner described.

It will be seen that the principle of the chart Amay be embodied in any of numerous constructions including embodiments in which the two charts are rectilinear and set by longitudinal slide relative to each other, and embodiments in which the adjustment is made by movement about the common axis of two coordinated cylindrical, conical or spherical chart elements.

Theembodiment shown, incorporating two simple discs relatively movable about a central pivot is of lowest cost and bulk and lends-itself readily to mass production. Obviously the calendar need not extend about the entire periphery of `such cylindrical, conical, spherical or disc element but could, if desired, extend over a sector thereof of any desired angle.

The invention thus affords a perpetual calendar in which all imprinted matter is at all times completely exposed to View, without the need for window openings to expose only selected parts, and inY which the entire calendar for any year of any century is set by but asingle adjustment and without the need for consulting V`separate tables or for making even simple comrelated charts relatively adjustable to determine the complete calendar for any selected year by a single adjustment, said two correlated charts including one chart bearing the complete sequence of months and days of the month arranged inA continuous uninterrupted sequences 'of rows and columns at right angles to each other, said chart having the name of each month `imprinted thereon in fixed correlation with the corresponding monthly chart ofthe correct number of days for each month, the correlated chart having thereon repeated sequences of the days ofthe week in position forfregistering with said rows,'one of said` relativelyV movable charts having imprinted-thereon an index of years, correlated with the respective columns and appropriately spaced for the ordinary sequence of years and for each leap year, whereby the calendar when correctly set for the current year may be shifted to any other yearof the century by corresponding shift of the other chart for registry with said year. v f

2. A perpetual calendar having a single chart of months and the days thereof imprinted thereon continuous uninterrupted sequences of rows and columns at right angles to each other, said chart having the nameof each month imprinted thereon in iixed correlation with` the corresponding monthly chart of the correct number of days each month and having a separate chart correlated therewith bearing repeated continuous sequences of the days ofthe week for registry with the days of the weekly rows and monthly columns, said two charts being adjustable relative to each other to register the day of the week for the particular selected year, an index of all the years of a century,V and an index of four consecutive centuries, one vof said indices being 0n the chart of months, said chart showing the numbers of the years correlated with the monthly columns, consecutive years involving an advance by one day, except for the last ten months of leap years, where the advance is by two days. y

3. The combination recited in claim 2 in which the leap years are indicated in manner discriminated from the ordinary years as is the extra day of the leap year;

4. A perpetual calendar comprising a calendar chart of months and days of the month, with the correct number of days for each month, said vmonths being arranged about a common center with the days in continuous uninterrupted sequence of annular rows and radiating columns,

, and a coordinated chart showing repeated cycles of the days of the week arranged in continuous circular sequence adjacent one end of the respective columns and adjustable in position to determine the setting for any one year, and index means of all of the years of the century imprinted on one of said charts and coordinated with the respective columns of lsuch chart, said index chart determining an advance of one day to each succeedingv ordinary year and two days to each succeeding leap year, whereby the complete calendar may be set by a single adjustment for any year of the century, the chart other than that bearing the index of years having imprinted thereon an index of four consecutive cenv`tures, said latter index determining the adjustment for the loss of two days to the next ordinary century and of but one day where the following century year is itself a leap year. y

5. A perpetual calendar comprising a calendar chart of months and days of the month, said months being arranged about a common center with the days in continuous uninterrupted sequence of annular rows and radiating columns, and a coordinated chartl showing repeated cycles of the days of the week arranged in continuous circular sequence adjacent one end of the respective columns and adjustable in position to determine the setting for any one year, and index means of all of the years of the century imprinted on one of said charts and coordinated to lie in the respective columns of such chart, said-index chart directing an advance` of one day to each succeeding ordinary year and two days to each succeeding leap year, whereby the complete calendar may be set by a single adjustment for any year of the century, said index having the leap years imprinted in discriminating type and said chart of months including an extra calendar of January and of the leap year February in such discriminating type, for use of such extra two months chart for leap years in lieu of the ordinary chart for said months which is employed for years other than leap years.

6. A perpetual calendar comprising a calendar chart of months and days of the month, said months being arranged about a common center with the days in continuous uninterrupted sequence of annular rows and radiating columns, and a coordinated chart showing repeated cycles of the days of the week arranged in continuous circular sequence adjacent one end of the respective columns and adjustable in position to determine the setting for any one year, and index means of all of the years of the century imprinted on one of said charts and coordinated with the respective columns of such chart, said index chart directing an advance of one day to each succeeding ordinary year and of two days to each succeeding leap year, whereby the complete calendar may be set by a single adjustment for any year of the century, said index having the leap years imprinted in discriminating type and said chart of months including an extra calendar of January and of the leap year February in such discriminating type for use of such extra two months chart for leap years in lieu of the ordinary chart for said months which is employed for years other than leap years, the chart other than that bearing the index of years having imprinted thereon an index of four consecutive centuries, said latter index directing the adjustment for the loss of two days to the next ordinary century and of but one day where the following century year is itself a leap year.

'7. A perpetual calendar comprising a pair of concentric uninterrupted discs, a complete calendar of months and days of the month imprinted in consecutive contiguous sectors on one of said discs, the days being arranged in continuous uninterrupted sequences of annular rows and radiating columns, repeated continuous sequences of the days of the week correlated therewith on the other of said discs about one of the peripheries of the chart of months, and an index of all the years of the century. distributed about the periphery of one of said charts with Sector spacing equal to that for a day of the month or the days of the week, said index directing an advance of one day to the next ordinary year and of two days to the next leap year, whereby a single setting effects adjustment of the complete calendar for any year, the chart other than that bearing the index of years having an index of centuries and showing four consecutive centuries each showing a lag of two days to the next ordinary century and of one day to that one of the four century years that is headed by a leap year, the extra day of the leap year being indicated in discriminating color to be disregarded for an ordinary year, whereby the setting of the numeral of the year on one chart in registry with the numeral of the century of the other chart will e'ect the complete calendar for that year of that century.

8. A perpetual calendar comprising a pair of concentric discs, each disc having a plurality of identical contiguous sectors, each sector presenting seven sub-sectors for the sequences of the days of the month, each sector having the name of the corresponding month imprinted thereon, the outer disc presenting the names of the days of the week in continuousrepeated sequences encompassing the inner disc, the inner disc having imprinted in bands concentric and within the imprint of months an index showing the consecutive years of the century aligned with consecutive sub-sectors of the chart of months and representing an advance of one day to the next ordinary year and of two days to the next leap year, said chart of months indicating the extra day of the leap year in discriminating type, to be disregarded for ordinary years, the other chart having an index of centuries, showing four consecutive centuries arranged in alignment with sub-sectors, said index directing a loss of two days with respect to the previous century and that one of the four century years which is headed by a leap year directing a loss of only one day with respect to the previous year, whereby a single adjustment of the device effects a setting for the complete ordinary calendar of any year.

9. A perpetual calendar comprising a chart of months and days of the month, the months being aligned in seven pairs, the J anuary-February pair being imprinted in duplicate with the extra pair in discriminating color and showing the extra day of the leap year, the sequence of days of the week being imprinted on a separate chart adjustable relative tov the chart of months to set the same for the calendar of any year, and an index of years correlated with one of said charts to determine the adjustment to any year, said index indicating an advance of one day in the calendar to the next ordinary year and of two days to the next leap year, the leap years being shown on the index in the same color as the extra leap year monthly calendar for January and February.

10. A perpetual calendar comprising a chart of months and days of the month, the months being aligned in seven pairs, each sector having imprinted thereon the titles and days of two consecutive months, the January-February pair being imprinted in duplicate with the extra pair in discriminating color and including the extra day of the leap year, the sequence of days of the week being imprinted on a separate sheet adjustable relative to the chart of months, to set the same for the calender of any year, and an index of the years of the century correlated with one of said charts to determine the adjustment to any year, said index directing an advance of one day in the calendar to the next ordinary year and of two days when the next year is a leap year, the leap years being shown on the index in the same color as the extra leap year calendar for January. and February, and an index of centuries coordinated with the index of years and directing the loss of two days in passing to each ordinary century and of only one day in passing to a century year which is itself a leap year.

11. A perpetual calendar comprising a disc shaped chart having imprinted thereon seven identical sectors extending completely thereabout, each sector having imprinted thereon the titles and days of two consecutive months, each sector being sub-divided into seven sub-sectors for the days of each week, one of the sectors carrying a duplication of the January and February calendar in a discriminating color and with the extra day of the leap year, an outer chart showing seven repeated sequences of the days of the week and encompassing the disc-shaped chart, a pivot connecting the inner to the outer chart, an index of years imprinted at the center portion of the smaller disc and serving to direct relative adjustment for the selected year, said index having the years of the century imprinted thereon in a sequence .arranged in three concen tric circles distributed over the forty-nine sub sectors of the chart of months, said sequence of years directing an advance of one day in passing to the next ordinary year and of two days where the next year is a leap year, the leap years being imprinted in the discriminating color of the extra January and February calendar.

12. A perpetual calendar comprising a discshaped chart having imprinted thereon seven identical sectors extending completely thereabout, each sector having imprinted thereon the titles and days of two consecutive months, each sector being sub-divided into seven sub-sectors for the days of each week, one of the sectors carrying a duplication of the January and February calendar in a discriminating color and with the extra day of the leap year, an outer chart showing seven repeated sequences of the days of the Week and encompassing the disc-shaped chart, a pivot connecting the inner to the outer chart, an index of years imprinted at the center portion of the smaller disc, .and serving to direct relative adjustment for the selected year, said index having the years of the century imprinted thereon in a sequence arranged in three concentric circles distributed over the forty-nine sub-sectors of the chart of months, said sequence of years directing an advance of one day in passing to the next ordinary year .and of two days where the next year is a leap year, the leap years being imprinted in the discriminating color of the extra January and February calendar, the outer or week day chart having imprinted thereon an index of centuries showing four consecutive centuries, 1800, 1900, 2000 and 2100, said century numerals being arranged in the sequence 1900, 1800, 2100 and 2000, there being a gap of one day between each century location and the next in the sequence stated, whereby there wiil be a loss of two days in passing to each ordinary century and of only one day in passing to a century year which is itself a leap year.

13. A perpetual calendar having a chart bearing the name and the sequence of the days of each month arranged in weekly rows, the rows of days of each month being in immediate sequence of those of the next month of the chart, said chart having associated therewith, a second chart bearing the sequence of days of the week in repeated cycles and adjustable relative to the rst chart, said calendar including an index of years of the century and an index of centuries, said indices being xed, one with respect to the sequence of days and the other with respect to the sequence of months, thereby to determine the setting for the complete calendar of any year of any century by aligning the selected year with the selected century.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 506,003 Dreyfus e Oct. 3, 1893 1,187,344 Langman June 13, 1916 2,036,398 Colvin Apr. '7, 1936 2,154,013 Schillaci Apr. 11, 1939 2,584,810 OKane Feb. 5, 1952 

